Inline metrology on air flotation for PCB applications

Patent metadata

Field	Value
Publication number	US-10458778-B2
Application number	US-201715816971-A
Country	US
Kind code	B2
Filing date	Nov 17, 2017
Priority date	Nov 17, 2016
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A measurement system measures various PCB panel characteristics, such as PCB panel thickness, surface feature thickness (height), surface feature width and length, and warpage. Various techniques are also described for steadying the PCB panel for measurement, whether the PCB panel is positioned horizontally or vertically. Z-height measurements as well as light intensity measurements can be used to determine the various PCB panel characteristics. Either the determined light intensity values, the determined Z-height values, or both can be used to determine pixel transition from one region, or material type, to another. Techniques are also provided to reduce PCB panel vibration and/or automatically adjusting a Z-height of the sensor to ensure a sampling point on the PCB panel is within an allowable Z-height range.

First claim

What is claimed is:

1. A measurement system comprising:
a. a printed circuit board panel comprising a substrate having a first side and a second side opposing the first side, wherein the first side comprises an insulating layer with a surface feature positioned on the insulating layer, wherein the surface feature is a conductive patterned interconnect;
b. a light emitter and detector device comprising a light source and a sensor, wherein the light emitter and detector device is positioned relative to the printed circuit board panel such that a light beam output from the light source impinges one or more sample points on the first side of the substrate, further wherein the sensor is configured to receive a reflected light corresponding to the light beam;
c. a movement and alignment apparatus coupled to the printed circuit board panel and the light emitter and detector device, wherein the movement and alignment apparatus is configured to provide relative movement between the light emitter and detector device and the printed circuit board panel and to scan the light beam over at least a portion of the first side of the printed circuit board panel; and
d. a controller configured to receive data from the sensor corresponding to the received reflected light and to determine a distance measurement corresponding to each sample point, and to determine a relative thickness of the printed circuit board panel and a height of the surface feature.

2. The measurement system of claim 1 wherein each sample point corresponds to a pixel of the light beam impinging the first side of the printed circuit board panel.

3. The measurement system of claim 2 wherein the light emitter and detector device is configured to emit the light beam focused as a point, wherein the light beam point impinges the first side of the printed circuit board panel as a single pixel.

4. The measurement system of claim 2 wherein the light emitter and detector device is configured to emit the light beam focused as a line, wherein the light beam line impinges the first side of the printed circuit board panel as a linear series of pixels.

5. The measurement system of claim 2 wherein the light emitter and detector device is configured to emit the light beam focused to impinge the first side of the printed circuit board panel as a two dimensional array of pixels.

6. The measurement system of claim 2 wherein the sensor is configured to sense pixel data according to each sample point.

7. The measurement system of claim 6 wherein light emitter and detector device is configured to determine the distance measurement corresponding for each pixel of the light beam impinging the printed circuit board panel.

8. The measurement system of claim 1 wherein the second side of the printed circuit board panel comprises a second insulating layer, and the light emitter and detector device is a first light emitter and detector device having a first light source and a first sensor, and the measurement system further comprises a second light emitter and detector device having a second light source and a second sensor, wherein the second light emitter and detector device is positioned relative to the printed circuit board panel such that a second light beam output from the second light source impinges one or more sample points on the second side of the substrate, further wherein the second sensor is configured to receive a second reflected light corresponding to the second light beam, further wherein the movement and alignment apparatus is coupled to the second light emitter and detector device, wherein the movement and alignment apparatus is further configured to provide relative movement between the second light emitter and detector device and the printed circuit board panel and to scan the second light beam over at least a portion of the second side of the printed circuit board panel, wherein the controller is further configured to receive data from the second sensor corresponding to the received second reflected light and to determine a distance measurement corresponding to each sample point on the second side, and to determine a relative thickness of the printed circuit board panel.

9. The measurement system of claim 8 wherein the movement and alignment apparatus is configured to move and align the first light emitter and detector device independently of the second light emitter and detector device.

10. The measurement system of claim 8 wherein the movement and alignment apparatus is configured to coordinate movement and alignment of the first light emitter and detector device and the second light emitter and detector device, such that the first light emitter and detector device and the second light emitter and detector device simultaneously scan aligned sample points on the first side and the second side of the printed circuit board assembly.

11. The measurement system of claim 10 wherein the controller is configured to determine a thickness of the printed circuit board panel at a specific sample point aligned on both the first side and the second side when the specific sample point is aligned with insulating layer on both the first light emitter and detector device and the second light emitter and detector device using the determined distance measurement from the first light emitter and detector device at the specific sample point and the determined distance measurement from the second light emitter and detector device at the specific sample point.

12. The measurement system of claim 11 wherein the controller is further configured to determine a height of the first surface feature at another specific sample point aligned on both the first side and the second side when the other specific sample point is aligned with the first surface feature on the first light emitter and detector device and with the insulating layer on the second light emitter and detector device using the determined distance measurement from the first light emitter and detector device at the other specific sample point and the determined distance measurement from the second light emitter and detector device at the other specific sample point.

13. The measurement system of claim 1 wherein the conductive patterned interconnect is a metal trace or a bond pad.

14. A measurement system comprising:
a. a printed circuit board panel comprising a substrate having a first side and a second side opposing the first side, wherein the first side comprises an insulating layer with an electrically conductive surface feature positioned on the insulating layer;
b. a light emitter and detector device comprising a light source and a sensor, wherein the light emitter and detector device is positioned relative to the printed circuit board panel such that a light beam output from the light source impinges one or more sample points on the first side of the substrate, further wherein the sensor is configured to receive a reflected light corresponding to the light beam, wherein each sample point corresponds to a pixel of the light beam impinging the first side of the printed circuit board panel, further wherein the sensor is configured to sense a light intensity value for each pixel, and the light emitter and detector device is configured to determine a light intensity measurement for each pixel;
c. a movement and alignment apparatus coupled to the printed circuit board panel and the light emitter and detector device, wherein the movement and alignment apparatus is configured to provide relative movement between the light emitter and detector device and the printed circuit board panel and to scan the light beam over at least a portion of the first side of the printed

Assignees

• Flex Ltd
• Multek Tech Limited

Inventors

• Glickman Michael James
• Nagle Brendan

Classifications

• H05K3/00

  Apparatus or processes for manufacturing printed circuits · CPC title

• G01B11/0691

  of objects while moving (G01B11/0616 takes precedence) · CPC title

• H05K1/02

  Details · CPC title

• G01B11/0608 Primary

  Height gauges · CPC title